1. FIELD OF THE INVENTION
This invention relates generally to the field of water purification devices and methods. More particularly, this invention relates to electro-chemical water purification devices particularly suited to treatment of swimming pool or spa water.
2. BACKGROUND
This invention purifies water by utilizing electrolysis to introduce copper ions into the water thereby inhibiting the growth of algae, fungi and bacteria. Such water purification techniques have many advantages, not the least of which is a substantial reduction in the need for addition of chemicals to swimming pool water thereby reducing the cost of operating a swimming pool. It also reduces the need for handling of, use of and exposure to liquid, granulated or gaseous chlorine products. While some degree of disinfectant action by chlorine or equivalents should still be used, the cost of such chemicals may be radically reduced with the present invention. In addition to the above advantages, the method and apparatus of the present invention allows for use of such electrolytic purification of the water while eliminating the need for drainage of the swimming pool to remove stabilizer from the water.
In U.S. Pat. No. 4,525,272 to Henson, an electrolytic water treatment apparatus is disclosed an embodiment of which is marketed by Swimaid, Inc. under the name "Challenger" (TM). This exemplary apparatus utilizes a cylindrical copper anode surrounded by a galvanized wire mesh cathode. The housing is fabricated to allow for a quick connection and disconnection from the pool filteration system and allows for quick replacement of the anode-cathode assembly by utilizing a standard plumbing sanitary T drain pipe fitting as the housing with the anode-cathode assembly installed on a plug cap having a connector designed to mate with those of the housing.
This arrangement has several drawbacks which are at least partially circumvented by the present invention. Not the least of these drawbacks is that the quick connect latches used in that design do not alone produce an adequate seal against leaks. Thus, rubber O-Rings are required to adequately seal the system. Such O-Rings are prone to fatigue which may ultimately result in leaks in the system. Also, depending upon the exact plumbing arrangement of the pool's filtration system, such quick connect latches are known to fail or disconnect upon receipt of the initial impact of water resulting when the pump of the filter system is initially turned on. Clearly this is an undesirable condition which can risk complete drainage of the pool within a few hours or possible loss of prime by the pump resulting in costly damage to the pump and/or refilling and conditioning of the pool water.
In addition, the water purifier disclosed in the above patent is only capable of operating over a narrow range of resistivity of water. While exact resistivity tests have not been done in the course of development of the present invention, it appears that the resistivity of water is roughly halved when a typical level of 30 to 100 ppm of cyanuric acid is present in the pool water. As such, swimming pools containing stabilizers such as Cyanuric Acid are unable to utilize that device. The electrical control circuitry of the above device has been observed to rapidly and frequently fail if used in swimming pools containing cyanuric acid. Since some amount of chlorine is practically a necessity in maintaining safe pool water, this limitation in the above device is a severe disadvantage. Those skilled in the art will recognize that cyanuric acid provides stabilization of chlorine thereby substantially slowing down the breakdown of chlorine by sunlight, etc. By requiring that the swimming pool be purged of cyanuric acid (by drainage of all pool water and refilling) the initial expense of installation of that device as well as inconvenience and risk of damage to the pool by drainage is increased. Furthermore, since all cyanuric acid must be purged from the pool, the amount and frequency with which chlorine products must be added to the pool are significantly increased thereby substantially reducing the convenience and economic advantage of using copper electrolysis to assist in the purifying process.
The above limitation also leads to a more costly and and possibly extended break-in period for the pool water after installation of the device. Since the pool must be drained and refilled as part of the installation process, and since cyanuric acid (or other subtances affecting the resistivity of the water) must not be introduced into the pool, large quantities of chlorine products may be required over a one to two month period while waiting for the level of copper to reach an effective level.
A further disadvantage of the above device is that its design (and indeed the teaching of the patent) requires that the water enter a side entrance to the housing where it is forced to abruptly change directions to produce a degree of turbulence to enhance the electrolytic activity. In so doing, the use of that device is limited to circumstances where adequate room is available for the various bends in pipe and other adaptation to the plumbing needed to effect such a change in direction. Such needs may have detrimental effects on the available water pressure when PVC pipe is used due to it's high friction with water. While this is generally not a serious drawback, the requirement for a direction change can make initial installation difficult and can become an additional consideration or cost in systems having solar heating equipment, automatic cleaners and other devices which require high water pressure to properly function. It can also become important in situations where only limited space for installation of such a device is possible.
The present invention relieves these and other shortcomings in the art with a novel water purifier having a simplified design which results in low cost assembly and more versatile performance as described in detail below.